Primer magazine cover for primer insert machine



April 25, 1961 R. E. DONNARD PRIMER MAGAZINE COVER FOR PRIMER INSERT MACHINE Filed May 8, 1958 OOOOOOOOOOO HHU OOOOOOOOOOO OOOOOOOOOOO OOOOOOOOO FIG.I.

INVEN TOR. REED E. DONNARD WWIQ QDM United States Patent PRIMER MAGAZINE COVER FOR PRINTER INSERT MACHINE Reed E. Donnard, 7809 Fillmore St., Philadelphia 11, Pa.

Filed May 8,1958, Ser. No. 734,064

1 Claim. (Cl. 86-38) (Granted under Title 35, US. Code (1952), see. 266) The invention described herein may be manufactured and used by or for the Government for governmental purposes without the payment of any royalty thereon.

This invention relates to primer magazines such as are utilized to feed primers to a primer insert machine, and more particularly to a primer magazine cover which is designed to limit the effect produced by accidental discharge of one or more primers while in the magazine.

Mass detonation of the primers in such a magazine results when the accidental discharge of one primer causes detonation of the remaining primers. Extensive tests have shown that sensitivity to mass detonation varies in primers from each manufacturer and from each lot of each manufacturer. It is also found that the use of a flat-surfaced magazine cover increased the tendency to mass detonation. The same is true where the primers are placed in a closed vessel. Thus in a state of partial or whole confinement of the primers, it was established that the flame envelopment and shock wave contributed large- 1y to mass detonation. I

The present invention avoids mass detonation of the primers by the provision of a magazine cover consisting of a flat plate which is slotted on its under surface to form primer row guides, these slots being perforated to localize the effect of an accidentalprimer discharge as hereinafter explained.

The invention will be better understood from the following description when considered in connection with the accompanying drawings and its scope is indicated by the appended claim.

Referring to the drawings:

Fig. 1 is a bottom view of the magazine cover, and

Fig. 2 is a section taken on the line 2-2 of Fig. 1.

The cover having a first surface 12 and a second surface 13 illustrated by these figures is made of a nonsparking conducting material, conforms to the shape of the magazine, and is provided with primer guideways 15 formed by the second surface 13 of the cover and continuous projections 14 adjacent the second surface. These primer guideways act as passageways and permit the primers to flow through the magazine in rows. The magazinc is tilted so that the primers are gravity fed toward the smaller end of the magazine. From the magazine, the primers go in single file to the transfer belt of the primer insert machine.

Perforations 11 are located in and along the primer guideways 15 through which the primers move. Those skilled in this art will understand that the standard primer cup and anvil in this country having a diameter of .210

inch are those intended for the most widely used small arms ammunition, namely .30 caliber cartridges. Tests show that a satisfactory relationship between the diameter of the perforations and the diameter of the primers is:

Diameter of vent hole .l56 Diameter of the primer .210

The center lines of these holes were separated by a quarter inch.

Accidental mass detonation, usually caused by accidental discharge of one primer, is eliminated by the abovevention.

I claim:

A cover for a primer magazine in which explosion sensitive type primers are arranged in rows, said cover being provided on an inner surface with elongated projections forming guideways or channels along which primers are moved from a magazine in single file to a transfer belt of a primer insert machine, said cover being vented to reduce the danger of mass detonation in event one primer might he accidentally fired, said cover being for small arms primers having a diameter of .210 inch, the base of each guideway or channel being vented throughout its length by substantially uniformly spaced holes and each hole having a diameter of about .156 inch, with the spacing between these holes between centers being about .25 inch whereby one primer may be fired without danger of other primers being ignited thereby.

References Cited in the file of this patent UNITED STATES PATENTS 

